[Gluster-users] error handling for cluster/replicate across 2 or more nodes

[John Preston]

I ask this because in a previous installation where I was running 1TB of
RAID1 (2 disks) under Centos 5, I noticed that after a few days the RAID
disk would go into readonly mode. When I unmounted it and rand a disk check
(fsck) it reported a whole bunch of errors of shared nodes, etc, all which
it fixed. However, after putting the disk back online the same problem
occurred a couple of days later. I checked the RAID disks independently for
bad blocks, etc and one of them was reporting some errors which were fixed.
In the end I had to replace the disk that kept reporting some errors, even
though I was told that they were fixed. When I did this, I no longer had the
problem.

So you can see what I'm trying to understand how gluster might deal with
such a case, if errors occurring in one of the replicated nodes would find
its way into the other nodes and corrupt them.

John

On Fri, Jul 9, 2010 at 10:37 PM, Emmanuel Noobadmin
<centos.admin at gmail.com>wrote:

> On 7/8/10, John Preston <byhisdeeds at gmail.com> wrote:
> > I am setting up a gluster configuration to replicate data across 3 nodes
> > using:
> >
> > volume afr-volume
> >   type cluster/replicate
> >   subvolumes brick1 brick2 brick3
> > end-volume
> >
> > Can someone say what safeguards exist with such a configuration to ensure
> > that if one of the nodes disks, starts to go bad and thus introduce
> errors
> > in one or more of the copies of files, that these bad sectors don't get
> > replicated across the cluster.
>
> I'm not certain but if the disk develops hard problems, I'll assume
> the host node will report it as an IO error and therefore the node is
> considered as failed? I suppose the problem would be if the node
> manages to read "something" after a retry.
>
> Just giving my 2cents and hoping to stir up some interest in this :)
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